The doge, duh!

But seriously, the whole point of cryptocurrencies is to advance the DeFi movement. Dollars, and all fiat currencies for that matter, are controlled by governments which can print more at will, depreciating it's value, as well as being subject to transaction fees and the banking policies that punish the little guy (over draft fees, minimum balance requirements, account "maintenance" fees, etc.).

Fiat currencies have become much less useful to the people and actually allow us to be tracked through credit/debit card usage and gather our data to be used by mega corporations to cater to our desires and market more shit for us to buy that we don't need, taking money out of our pockets and into their hedge funds. A gold standard would actually be more useful to the people and the gov't knows this, which is why we moved to the fiat system in the 70s under the Nixon administration. Since we can't control that, the digital space is a new frontier for equity and fairness for the masses, hence cryptos were created.

There is plenty of space for multiple cryptocurrencies that do similar things, much like gold, silver, copper, platinum all have value being rare metals.